Clock signals may play many roles in synchronous systems. For example, data movement in various elements of a synchronous circuit may be referenced by one or more clock signals. In some cases, a large, pipelined circuit may comprise numerous clocked elements such as latches, flip-flops, and the like. In others, a synchronous circuit may comprise one or more clock domains each operating at a different frequency. These are just a few of the uses of clock signals in synchronous systems.